Lagrangian Observations of Sulfur Aerosol Dynamics
Near Tasmania During ACE-1

We measured nonseasalt sulfate (NSS) and methanesulfonate (MSA) in
particles < 1 um in diameter from the NCAR C-130 during the ACE-1
experiment. On two occasions we followed the evolution of airmasses for
more than 24 hours by tagging the air with smart balloons and using their
GPS-derived locations to make multiple flights into the same air. Since
the air was moving toward colder water, the boundary layer tended to be
stable, with only a small surface mixed layer. This complicates the
process of constructing chemical budgets.

In both Lagrangian experiments, we noted that the concentrations of MSA
and NSS increased during the daytime and remained relatively constant at
night. This is consistent with their production by photochemical
mechanisms. We will discuss formation mechanisms and infer rates from the
observed concentration changes.